Immunochemical changes in the maturing (neonate through adult) mouse kidney will be evaluated by their reactivity to specific antisera. Specifically this will employ antistreptococcal cell membrane (SCM) and antihuman glomerular basement membrane (GBM) sera obtained from previous studies and whose reactivities have been characterized. Thus the localization on kidney sections of fluorescent antibody within age groupings could be correlated to specificity of the antisera thereby defining the chemical composition of the antigenic site. Some antisera are carbohydrate (CHO) specific while others are protein specific. The final confirmation would be accomplished via isolation of the specific reactive GBM and its subsequent chemical composition determined. Additionally peptide profiles will be obtained and by specific immunoadsorption columns key peptides can be isolated and confirmed for their involvement in the specific reaction previously determined. Thus specific structural maturation changes can be isolated and subsequently their chemical composition elucidated.